Polyurea/polythiourea coatings

ABSTRACT

Polyurea/polythiourea compositions comprising the reaction product of a first component comprising isocyanate and a second component comprising an amine, wherein the first and/or second component further comprises a sulfur-containing compound are disclosed. Methods for using the coating, and substrates coated therewith, are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority to U.S. Provisional PatentApplication 60/797,985 filed on May 5, 2006.

FIELD OF THE INVENTION

The present invention is directed to a coating composition comprisingpolyurea and polythiourea.

BACKGROUND OF THE INVENTION

Coating compositions comprising polyureas are used in a wide variety ofindustries such as automotive, watercraft, aircraft, industrial,construction, military, recreational equipment including sportsequipment and the like. In these industries, considerable efforts havebeen made to develop coating compositions that will impart the desiredproperties to the substrate or article being coated. For example,coatings are used to protect against damage due to corrosion, abrasion,impact, chemicals, ultraviolet light, flame, heat, and/or otherenvironmental exposure. In addition to any of these functionalproperties, coatings can also be used for decorative purposes.

Sulfur-containing compounds are known to be well suited for use inaerospace sealants due to their fuel resistant nature upon crosslinking.For example, polysulfide sealants can offer high tensile strength, hightear strength, thermal resistance and resistance to high ultravioletlight. Such sealants can also offer resistance to fuel and maintaintheir adhesion upon exposure to fuel.

Polyureas are generally formed by reacting amines and isocyanates. Theuse of amines such as polyamines as crosslinkers or “curatives” is wellknown. For example, amines are known to crosslink with isocyanates toform urea compounds. Similarly, sulfur-containing compounds are known tocrosslink with isocyanates to form thiourea compounds. The use ofsulfur-containing compounds in a polyurea coating, however, has beendifficult due to the high viscosity and odor of the sulfur-containingcompounds. Combinations, however, would be desirable to provide optimumproperties.

SUMMARY OF THE INVENTION

The present invention is directed to a coating composition comprisingpolyurea and polythiourea formed from a reaction mixture comprising afirst component comprising isocyanate, a second component comprising anamine, and a sulfur-containing compound in the first and/or secondcomponent.

The present invention is further directed to methods for coating asubstrate using such coatings, and substrates coated thereby.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a coating composition comprisingpolyurea and polythiourea formed from a reaction mixture comprising afirst component comprising isocyanate (“isocyanate component”), a secondcomponent comprising an amine (“amine component”), and asulfur-containing compound in the first and/or second component. Theamine component may be referred to herein as a “curative” because itwill react or cure with the isocyanate to form a polyurea and/or apolythiourea. In certain embodiments, the ratio of equivalents ofisocyanate groups to equivalents of amine/mercaptan groups is greaterthan 1 and the isocyanate component and the amine component can beapplied to a substrate at a volume mixing ratio of 1:1. The terms“mercaptan” and variants thereof and “thiol” and variants thereof areused interchangeably herein.

As used herein, the term “isocyanate” includes unblocked compoundscapable of forming a covalent bond with a reactive group such as ahydroxyl, mercaptan or amine functional group. Thus, isocyanate canrefer to “free isocyanate”, which will be understood to those skilled inthe art. In alternate non-limiting embodiments, the isocyanate of thepresent invention can be monofunctional containing one isocyanatefunctional group (NCO) or the isocyanate used in the present inventioncan be polyfunctional containing two or more isocyanate functionalgroups (NCOs).

Suitable isocyanates for use in the present invention are numerous andcan vary widely. Such isocyanates can include those that are known inthe art. Non-limiting examples of suitable isocyanates can includemonomeric and/or polymeric isocyanates. The polyisocyanates can beselected from monomers, prepolymers, oligomers, or blends thereof. In anembodiment, the polyisocyanate can be C₂-C₂₀ linear, branched, cyclic,aromatic, or blends thereof.

Suitable isocyanates for use in the present invention may include butare not limited to isophorone diisocyanate (IPDI), which is3,3,5-trimethyl-5-isocyanato-methyl-cyclohexyl isocyanate; hydrogenatedmaterials such as cyclohexylene diisocyanate, 4,4′-methylenedicyclohexyldiisocyanate (H₁₂MDI); mixed aralkyl diisocyanates such astetramethylxylyl diisocyanates, OCN—C(CH₃)₂—C₆H₄C(CH₃)₂—NCO;polymethylene isocyanates such as 1,4-tetramethylene diisocyanate,1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate (HMDI),1,7-heptamethylene diisocyanate, 2,2,4- and 2,4,4-trimethylhexamethylenediisocyanate, 1,10-decamethylene diisocyanate and2-methyl-1,5-pentamethylene diisocyanate; and mixtures thereof.

Non-limiting examples of aromatic isocyanates for use in the presentinvention may include but are not limited to phenylene diisocyanate,toluene diisocyanate (TDI), xylene diisocyanate, 1,5-naphthalenediisocyanate, chlorophenylene 2,4-diisocyanate, bitoluene diisocyanate,dianisidine diisocyanate, tolidine diisocyanate, alkylated benzenediisocyanates, methylene-interrupted aromatic diisocyanates such asmethylenediphenyl diisocyanate, 4,4′-isomer (MDI) including alkylatedanalogs such as 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate,polymeric methylenediphenyl diisocyanate and mixtures thereof.

In a non-limiting embodiment, polyisocyanate monomer may be used. It isbelieved that the use of a polyisocyanate monomer (i.e., residual-freemonomer from the preparation of prepolymer) may decrease the viscosityof the polyurea/polythiourea composition thereby improving itsflowability, and may provide improved adhesion of thepolyurea/polythiourea coating to a previously applied coating and/or toan uncoated substrate. For example, the coatings that have beenpreviously applied to a substrate can comprise functional groups (e.g.hydroxy groups) that are reactive with isocyanates, thereby enhancingadhesion of this coating to the polyurea/polythiourea composition of thepresent invention applied over this coating. A lower viscositypolyurea/polythiourea composition may also remain in a “flowable” statefor a longer period of time as compared to a comparable compositionhaving a higher viscosity. In alternate embodiments of the presentinvention, at least 1 percent by weight, or at least 2 percent byweight, or at least 4 percent by weight of the isocyanate componentcomprises at least one polyisocyanate monomer.

In a further embodiment of the invention, the isocyanate can includeoligomeric polyisocyanates including but not limited to dimers, such asthe uretdione of 1,6-hexamethylene diisocyanate, trimers, such as thebiuret and isocyanurate of 1,6-hexanediisocyanate and the isocyanurateof isophorone diisocyanate, allophonates and polymeric oligomers.Modified polyisocyanates can also be used, including but not limited tocarbodiimides and uretdiones, and mixtures thereof. Suitable materialsinclude, without limitation, those available under the designationDESMODUR from Bayer Corporation of Pittsburgh, Pa. and include DESMODURN 3200, DESMODUR N 3300, DESMODUR N 3400, DESMODUR XP 2410, and DESMODURXP 2580.

As used herein, “isocyanate prepolymer” includes polyisocyanate that ispre-reacted with a polyamine, sulfur-containing compound having areactive group and/or another isocyanate reactive group such as polyol.Suitable polyisocyanates include those previously disclosed herein.Suitable polyamines are numerous and may be selected from a wide varietyknown in the art. Examples of suitable polyamines include but are notlimited to primary and secondary amines, and mixtures thereof, such asany of those listed herein. Amine terminated polyureas may also be used.Amines comprising tertiary amine functionality can be used provided thatthe amine further comprises at least two primary and/or secondary aminogroups. Suitable polyols are numerous and may be selected from a widevariety known in the art. Examples of suitable polyols include but arenot limited to polyether polyols, polyester polyols, polyurea polyols(e.g. the Michael reaction product of an amino function polyurea with ahydroxyl functional (meth)acrylate), polycaprolactone polyols,polycarbonate polyols, polyurethane polyols, poly vinyl alcohols,addition polymers of unsaturated monomers with pendant hydroxyl groupssuch as those containing hydroxy functional (meth)acrylates, allylalcohols and mixtures thereof.

In certain embodiments, the isocyanate includes an isocyanate prepolymerand in other embodiments the isocyanate includes an isocyanateprepolymer and one or more additional isocyanates, such as one or moreof the polyisocyanates described above.

As noted above, the polyurea/polythiourea of the present compositions isformed from a reaction mixture comprising an isocyanate component and anamine component.

Suitable amines for use in the amine component of the present inventioncan be selected from a wide variety of known amines, such as primary andsecondary amines, and mixtures thereof including polyamines having atleast two functional groups, such as di-, tri-, or higher functionalpolyamines and mixtures thereof. The amine or amines used may bearomatic or aliphatic, such as cycloaliphatic, or mixtures thereof.Suitable monoamines include but are not limited to primary amines of theformula R₈—NH₂, where R₈ is a hydrocarbon radical that may represent astraight chain or branched alkyl group, an aryl-alkyl group, ahydroxyalkyl group or an alkoxyalkyl group. Other examples of suitablealiphatic mono and polyamines include but are not limited to ethylamine,isomeric propylamines, butylamines (e.g. butylamine, isobutylamine,sec-butylamine, and tert-butylamine), pentylamines, hexylamines,cyclohexylamine, ethylene diamine, 1,2-diaminopropane,1,4-diaminobutane, 1,3-diaminopentane (DYTEK EP, Invista),1,6-diaminohexane, 2-methyl-1,5-pentane diamine (DYTEK A, Invista),2,5-diamino-2,5-dimethylhexane, 2,2,4- and/or2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane,1,12-diaminododecane, 1,3- and/or 1,4-cyclohexane diamine,1-amino-3,3,5-trimethyl-5-aminomethyl-cyclohexane, 2,4- and/or2,6-hexahydrotoluoylene diamine, 2,4′-diaminodicyclohexyl methane,4,4′-diaminodicyclohexyl methane (PACM-20, Air Products) and3,3′-dialkyl-4,4′-diaminodicyclohexyl methanes (such as3,3′-dimethyl-4,4′-diaminodicyclohexyl methane (DIMETHYL DICYKAN orLAROMIN C260, BASF; ANCAMINE 2049, Air Products) and3,3′-diethyl-4,4′-diaminodicyclohexyl methane), 2,4- and/or2,6-diaminotoluene and 2,4′- and/or 4,4′-diaminodiphenyl methane, ormixtures thereof. Additional suitable amines include but are not limitedto 2-ethylhexylamine, octylamine, tert-octylamine, dodecylamine,octadecylamine, 3-(cyclohexylamine)propylamine,3,3′-[1,4-butanediylbis]-1-propanamine, and diamino functionalpolyetheramines having aliphatically bound primary amino groups,examples of which include JEFFAMINE D-230, JEFFAMINE D-400, JEFFAMINED-2000, and JEFFAMINE D-4000 available from Huntsman Corporation. Itwill be appreciated that when the amine is hindered, the reaction timebetween the amine and the isocyanate may be slower. This gives a longerpot-life or work-processing time in those situations where a longerprocessing time is desired.

In certain embodiments the polyamine is a triamine. Examples of suitabletriamines include dipropylene triamine, bis(hexamethylene) triamine andtriamino functional polyetherpolyamines having aliphatically boundprimary amino groups (JEFFAMINE T-403, JEFFAMINE T-3000, JEFFAMINET-5000 from Huntsman Corporation.) In other embodiments the amine can bea tetraamine or other higher functional amine.

The amine component may comprise an amine/(meth)acrylate oligomericreaction product, and/or one or more other amine curatives. As usedherein, and as will be appreciated by those skilled in the art,“(meth)acrylate” and like terms refers to both the acrylate and thecorresponding methacrylate. For example, the second component maycomprise one or more amines that are the reaction product of apolyamine, a poly(meth)acrylate, and a mono(meth)acrylate or amonoamine, such as those described in U.S. patent application Ser. No.11/611,979, incorporated by reference herein; one or more amines thatare the reaction product of an amine, a (meth)acrylate and a dialkylmaleate and/or dialkyl fumarate, such as those described in U.S. patentapplication Ser. No. 11/611,988, incorporated by reference herein; oneor more amines that are the reaction product of a polyamine and amono(meth)acrylate, such as those described in U.S. patent applicationSer. No. 11/611,982, incorporated by reference herein; one or moreamines that are the reaction product of a monoamine and a(meth)acrylate, such as those described in U.S. patent application Ser.No. 11/611,984, incorporated by reference herein; and/or one or moreamines that are the reaction product of a triamine and a dialkyl maleateand/or dialkyl fumarate, such as those described in U.S. patentapplication Ser. No. 11/611,986, incorporated by reference herein.

The present compositions, as noted above, can additionally include otheramines, such as those known in the art including but not limited to anypolyamines or combinations thereof listed herein. Other amines includesecondary cycloaliphatic diamines such as JEFFLINK 754 (HuntsmanCorporation, Houston, Tex.) and CLEARLINK 1000 (Dorf-Ketal Chemicals,LLC), aspartic ester functional amines, such as those available underthe name DESMOPHEN such as DESMOPHEN NH1220, DESMOPHEN NH 1420, andDESMOPHEN NH 1520 (Bayer Corporation), other aspartic ester functionalmaterials, such as the reaction products of triamines that comprise atleast one secondary amino group prior to reaction with a dialkyl maleateand/or dialkyl fumarate including but not limited to the reactionproducts of diethylene triamine, dipropylene triamine, andbis-hexamethylene triamine with a dialkyl maleate and/or dialkylfumarate; examples of such materials include the adduct of dipropylenetriamine and diethyl maleate, the adduct of dipropylene triamine anddibutyl maleate, the adduct of bis-hexamethylene triamine with diethylmaleate, and the adduct of bis-hexamethylene triamine with dibutylmaleate. Polyoxyalkyleneamines are also suitable. Polyoxyalkyleneaminescomprise two of more primary or secondary amino groups attached to abackbone, derived, for example, from propylene oxide, ethylene oxide,butylene oxide or a mixture thereof. Examples of such amines includethose available under the designation JEFFAMINE, such as, withoutlimitation, JEFFAMINE D-230, D-400, D-2000, HK-511, ED-600, ED-900,ED-2003, T-403, T-3000, T-5000, SD-231, SD-401, SD-2001, and ST-404(Huntsman Corporation). Such amines have an approximate molecular weightranging from 200 to 7500.

Other suitable secondary amines that can be included in the presentcomposition are reaction products of materials comprising primary aminefunctionality with acrylonitrile. Suitable amines include any polyaminelisted herein comprising primary amino functionality. One example ofsuch a material is the adduct of 4,4′-diaminodicyclohexylmethane andacrylonitrile. An example of a commercially available material is theadduct of isophorone diamine and acrylonitrile sold under thedesignation POLYCLEAR 136, (Hansen Group LLC).

Other amines that can be used are adducts of primary polyamines withmono or polyepoxies; an example of such a material is the adduct ofisophorone diamine with CARDURA E10P (available from Hexion SpecialityChemicals, Inc).

In certain embodiments, the second component of the composition, and/orthe composition itself, are substantially free of primary aminefunctionality (unreacted primary amino groups). “Substantially free ofprimary amine functionality” and like terms means that theoreticallythere is no primary amine functionality but there maybe some primaryamine functionality present that is purely incidental, i.e. impuritiesin amines that are otherwise secondary amine functional and/or traceprimary amine functionality that did not react.

As noted above, the first and/or second component of the presentcompositions further comprises a sulfur-containing compound. As usedherein, the term “sulfur-containing compound” refers to any compoundhaving at least one sulfur atom, including, but not limited to, a thiol,a polythiol, a thioether, a polythioether and a polysulfide. A “thiol”as used herein refers to a compound having a thiol or mercaptan group,that is, an “SH” group. A “polythiol” refers to such a compound havingmore than one SH group, such as a dithiol or higher functionality thiol.Such groups are typically terminal and/or pendent such that they have anactive hydrogen that is reactive with other functional groups. A“thioether” or “polythioether” refers to a compound that contains one ormore sulfur atoms, respectively, such as within the backbone of thepolymer, that do not contain an active hydrogen group; that is, they arebonded on either side to another sulfur atom, a carbon atom, and thelike. A “polythiol” can comprise both a terminal and/or pendant sulfur(—SH) and a non-reactive sulfur atom (—S—). Thus, the term “polythiol”generally encompassed “polythioether” as well. Suitable polythiolsinclude, for example, those disclosed in U.S. Pat. No. 7,009,032,incorporated by reference herein. Any sulfur-containing compound usedaccording to the present invention can further comprise additionalfunctionality, including but not limited to hydroxyl functionality andepoxy functionality.

The sulfur-containing compound can also be the form of a prepolymer.This is particularly relevant if the sulfur-containing compound is inthe isocyanate component. It will be appreciated that inclusion of asulfur-containing compound having an active hydrogen in the isocyanatecomponent will result in a reaction between the active hydrogen and theisocyanate. Accordingly, when used in the isocyanate component, thesulfur-containing compound should have substantially no residual activehydrogens that will react with the isocyanate. A prepolymer formedbetween the sulfur-containing compound and the isocyanate can be made,such as one prepared by reacting a mercaptan terminated disulfide withan isocyanate.

In certain embodiments, the polythiol comprises a thioether-functionalpolythiol prepared by reacting together compound (a) having at least twothiol functional groups, and compound (b) having triple bondfunctionality. In certain embodiments, the compound having triple bondfunctionality will be a hydroxyl functional compound, and thethioether-functional polythiol will have pendant hydroxyl functionalgroups.

The compound (a) having at least two thiol functional groups maycomprise, for example, a polythiol or mixture thereof. A “polythiol” asused herein refers to a dithiol or a higher polythiol. In certainembodiments, the polythiol comprises dithiol, and in certain embodimentsthe polythiol comprises a mixture of a dithiol and another compoundhaving more than two thiol functional groups (higher polythiol). Suchmixtures may include mixtures of dithiols and/or mixtures of higherpolythiols. The thiol functional groups (—SH groups) are typicallyterminal groups, though a minor portion (such as less than 50%, or lessthan 25%, of all thiol groups) may be pendant along a chain. Thecompound (a) may additionally contain a minor portion (such as less than50%, or less than 25%, of all functional groups) of other activehydrogen functionality (that is, different from thiol), for example,hydroxyl functionality. The compound (a) may be linear or branched, andmay contain cyclic, alkyl, aryl, aralkyl, or alkaryl groups.

The compound (a) can be selected so as to produce a substantially linearoligomeric polythiol. Therefore, when compound (a) comprises a mixtureof a dithiol and a compound having more than two thiol functionalgroups, the compound having more than two thiol functional groups can bepresent in an amount that will maintain the linear nature of thepolymer, such as up to 10 percent by weight of the mixture.

Suitable dithiols can include linear or branched aliphatic,cycloaliphatic, aromatic, heterocyclic, polymeric, oligomeric dithiolsand mixtures thereof. The dithiol can comprise a variety of linkagesincluding but not limited to ether linkages (—O—), sulfide linkages(—S—), polysulfide linkages (—S_(x)—, wherein x is at least 2, such asfrom 2 to 4) and combinations of such linkages.

Non-limiting examples of suitable dithiols for use in the presentinvention can include but are not limited to2,5-dimercaptomethyl-1,4-dithiane, dimercaptodiethylsulfide (DMDS),ethanedithiol, 3,6-dioxa-1,8-octanedithiol, ethylene glycoldi(2-mercaptoacetate), ethylene glycol di(3-mercaptopropionate),poly(ethylene glycol) di(2-mercaptoacetate) and poly(ethylene glycol)di(3-mercaptopropionate), benzenedithiol,4-tert-butyl-1,2-benzenedithiol, 4,4′-thiodibenzenethiol, and mixturesthereof.

The dithiol may include dithiol oligomers having disulfide linkages suchas materials represented by the following graphic formula I:

wherein n can represent an integer from 1 to 21.

Dithiol oligomers represented by Formula I can be prepared, for example,by the reaction of 2,5-dimercaptomethyl-1,4-dithiane with sulfur in thepresence of basic catalyst, as known in the art.

The nature of the SH group in polythiols is such that oxidative couplingcan occur readily, leading to formation of disulfide linkages (that is,—S—S— linkages). Various oxidizing agents can lead to such oxidativecoupling. The oxygen in the air can in some cases lead to such oxidativecoupling during storage of the polythiol. It is believed that a possiblemechanism for the oxidative coupling of thiol groups involves theformation of thiyl radicals, followed by coupling of said thiylradicals, to form disulfide linkage. It is further believed thatformation of a disulfide linkage can occur under conditions that canlead to the formation of a thiyl radical, including but not limited toreaction conditions involving free radical initiation. The polythiolsfor use as compound (a) in the preparation of the polythiols of thepresent invention can include species containing disulfide linkagesformed during storage.

The polythiols for use as compound (a) in the preparation of theoligomeric polythiols used in certain embodiments of the presentinvention also can include species containing disulfide linkages formedduring synthesis of the polythiol.

In certain embodiments, the dithiol for use in the present invention caninclude at least one dithiol represented by the following graphicformulas:

The sulfide-containing dithiols comprising 1,3-dithiolane (e.g.,formulas II and III) or 1,3-dithiane (e.g., formulas IV and V) can beprepared by reacting asym-dichloroacetone with dimercaptan, and thenreacting the reaction product with dimercaptoalkylsulfide, dimercaptanor mixtures thereof, as described in U.S. Pat. No. 7,009,032 B2.

Non-limiting examples of suitable dimercaptans for use in the reactionwith asym-dichloroacetone can include but are not limited to materialsrepresented by the following formula VI:

wherein Y can represent CH₂ or (CH₂—S—CH₂), and n′ can be an integerfrom 0 to 5. The dimercaptan for reaction with asym-dichloroacetone inthe present invention can be chosen from, for example, ethanedithiol,propanedithiol, and mixtures thereof.

The amount of asym-dichloroacetone and dimercaptan suitable for carryingout the above reaction can vary. For example, asym-dichloroacetone anddimercaptan can be present in the reaction mixture in an amount suchthat the molar ratio of dichloroacetone to dimercaptan can be from 1:1to 1:10.

Suitable temperatures for reacting asym-dichloroacetone with dimercaptancan vary, often ranging from 0 to 100° C.

Non-limiting examples of suitable dimercaptans for use in the reactionwith the reaction product of the asym-dichloroacetone and dimercaptancan include but are not limited to materials represented by the abovegeneral formula VI, aromatic dimercaptans, cycloalkyl dimercaptans,heterocyclic dimercaptans, branched dimercaptans, and mixtures thereof.

Non-limiting examples of suitable dimercaptoalkylsulfides for use in thereaction with the reaction product of the asym-dichloroacetone anddimercaptan include but are not limited to materials represented by thefollowing formula:

wherein X can represent O, S or Se, n″ can be an integer from 0 to 10, mcan be an integer from 0 to 10, p can be an integer from 1 to 10, q canbe an integer from 0 to 3, and with the proviso that (m+n″) is aninteger from 1 to 20.

Non-limiting examples of suitable dimercaptoalkylsulfides for use in thepresent invention can include branched dimercaptoalkylsulfides.

The amount of dimercaptan, dimercaptoalkylsulfide, or mixtures thereof,suitable for reacting with the reaction product of asym-dichloroacetoneand dimercaptan, can vary. Typically, dimercaptan,dimercaptoalkylsulfide, or a mixture thereof, can be present in thereaction mixture in an amount such that the equivalent ratio of reactionproduct to dimercaptan, dimercaptoalkylsulfide, or a mixture thereof,can be from 1:1.01 to 1:2. Moreover, suitable temperatures for carryingout this reaction can vary within the range of from 0 to 100° C.

The reaction of asym-dichloroacetone with dimercaptan can be carried outin the presence of an acid catalyst. The acid catalyst can be selectedfrom a wide variety known in the art, such as but not limited to Lewisacids and Bronsted acids. Non-limiting examples of suitable acidcatalysts can include those described in Ullmann's Encyclopedia ofIndustrial Chemistry, 5^(th) Edition, 1992, Volume A21, pp. 673 to 674.The acid catalyst is often chosen from boron trifluoride etherate,hydrogen chloride, toluenesulfonic acid, and mixtures thereof. Theamount of acid catalyst can vary from 0.01 to 10 percent by weight ofthe reaction mixture.

The reaction product of asym-dichloroacetone and dimercaptan canalternatively be reacted with dimercaptoalkylsulfide, dimercaptan ormixtures thereof, in the presence of a base. The base can be selectedfrom a wide variety known in the art, such as but not limited to Lewisbases and Bronsted bases. Non-limiting examples of suitable bases caninclude those described in Ullmann's Encyclopedia of IndustrialChemistry, 5^(th) Edition, 1992, Volume A21, pp. 673 to 674. The base isoften sodium hydroxide. The amount of base can vary. Typically, asuitable equivalent ratio of base to reaction product of the firstreaction, can be from 1:1 to 10:1.

The reaction of asym-dichloroacetone with dimercaptan can be carried outin the presence of a solvent. The solvent can be selected from but isnot limited to organic solvents. Non-limiting examples of suitablesolvents can include but are not limited to chloroform, dichloromethane,1,2-dichloroethane, diethyl ether, benzene, toluene, acetic acid andmixtures thereof.

In another embodiment, the reaction product of asym-dichloroacetone anddimercaptan can be reacted with dimercaptoalkylsulfide, dimercaptan ormixtures thereof, in the presence of a solvent, wherein the solvent canbe selected from but is not limited to organic solvents. Non-limitingexamples of suitable organic solvents can include alcohols such as butnot limited to methanol, ethanol and propanol; aromatic hydrocarbonsolvents such as but not limited to benzene, toluene, xylene; ketonessuch as but not limited to methyl ethyl ketone; water; and mixturesthereof.

The amount of solvent can widely vary, from 0 to 99 percent by weight ofthe reaction mixtures. Alternatively, the reactions can be carried outneat, i.e., without solvent.

The reaction of asym-dichloroacetone with dimercaptan can also becarried out in the presence of a dehydrating reagent. The dehydratingreagent can be selected from a wide variety known in the art. Suitabledehydrating reagents for use in this reaction can include but are notlimited to magnesium sulfate. The amount of dehydrating reagent can varywidely according to the stoichiometry of the dehydrating reaction.

The compound (a) having at least two thiol functional groups used toprepare the oligomeric polythiol used in certain embodiments of thepresent invention can be prepared in certain non-limiting embodiments byreacting 2-methyl-2-dichloromethyl-1,3-dithiolane withdimercaptodiethylsulfide to produce dimercapto-1,3-dithiolane derivativeof formula III. Alternatively, 2-methyl-2-dichloromethyl-1,3-dithiolanecan be reacted with 1,2-ethanedithiol to producedimercapto-1,3-dithiolane derivative of formula II.2-methyl-2-dichloromethyl-1,3-dithiane can be reacted withdimercaptodiethylsulfide to produce dimercapto-1,3-dithiane derivativeof formula V. Also, 2-methyl-2-dichloromethyl-1,3-dithiane can bereacted with 1,2-ethanedithiol to produce dimercapto-1,3-dithianederivative of formula IV.

Another non-limiting example of a dithiol suitable for use as compound(a) in the preparation of the oligomeric polythiol used in certainembodiments of the present invention can include at least one dithiololigomer prepared by reacting dichloro derivative withdimercaptoalkylsulfide as follows in Reaction Scheme A:

wherein R can represent CH₃, CH₃CO, C₁ to C₁₀ alkyl, cycloalkyl, arylalkyl, or alkyl-CO; Y′ can represent C₁ to C₁₀ alkyl, cycloalkyl, C₆ toC₁₄ aryl, (CH₂)_(p′)(S)_(m′)(CH₂)_(q′), (CH₂)_(p′)(Se)_(m′)(CH₂)_(q′),(CH₂)_(p′)(Te)_(m′)(CH₂)_(q′) wherein m′ can be an integer from 1 to 5and, p′ and q′ can each be an integer from 1 to 10; n′″ can be aninteger from 1 to 20; and x can be an integer from 0 to 10.

The reaction of dichloro derivative with dimercaptoalkylsulfide can becarried out in the presence of a base. Suitable bases include any knownto those skilled in the art in addition to those disclosed above.

The reaction of dichloro derivative with dimercaptoalkylsulfide may becarried out in the presence of a phase transfer catalyst. Suitable phasetransfer catalysts for use in the present invention are known andvaried. Non-limiting examples can include but are not limited totetraalkylammonium salts and tetraalkylphosphonium salts. This reactionis often carried out in the presence of tetrabutylphosphonium bromide asphase transfer catalyst. The amount of phase transfer catalyst can varywidely, from 0 to 50 equivalent percent, or from 0 to 10 equivalentpercent, or from 0 to 5 equivalent percent, relative to thedimercaptosulfide reactants.

The compound (a) having at least two thiol functional groups may furthercontain hydroxyl functionality. Non-limiting examples of suitablepolythiol materials having hydroxyl groups can include but are notlimited to glycerin bis(2-mercaptoacetate), glycerinbis(3-mercaptopropionate), 1,3-dimercapto-2-propanol,2,3-dimercapto-1-propanol, trimethylolpropane bis(2-mercaptoacetate),trimethylolpropane bis(3-mercaptopropionate), pentaerythritolbis(2-mercaptoacetate), pentaerythritol tris(2-mercaptoacetate),pentaerythritol bis(3-mercaptopropionate), pentaerythritoltris(3-mercaptopropionate), and mixtures thereof.

In addition to dithiols disclosed above, particular examples of suitabledithiols for use as or in preparing the compound (a) can include1,2-ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol,1,3-butanedithiol, 1,4-butanedithiol, 2,3-butanedithiol,1,3-pentanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol,1,3-dimercapto-3-methylbutane, dipentenedimercaptan,ethylcyclohexyldithiol (ECHDT), dimercaptodiethylsulfide (DMDS),methyl-substituted dimercaptodiethylsulfide, dimethyl-substituteddimercaptodiethylsulfide, 3,6-dioxa-1,8-octanedithiol,1,5-dimercapto-3-oxapentane, 2,5-dimercaptomethyl-1,4-dithiane (DMMD),ethylene glycol di(2-mercaptoacetate), ethylene glycoldi(3-mercaptopropionate), and mixtures thereof.

Suitable trifunctional or higher-functional polythiols for use incompound (a) can be selected from a wide variety known in the art.Non-limiting examples can include pentaerythritoltetrakis(2-mercaptoacetate), pentaerythritoltetrakis(3-mercaptopropionate), trimethylolpropanetris(2-mercaptoacetate), trimethylolpropane tris(3-mercaptopropionate),and/or thioglycerol bis(2-mercaptoacetate).

For example, the polythiol can be chosen from materials represented bythe following formula VIII,

wherein R₁ and R₂ can each be independently chosen from straight orbranched chain alkylene, cyclic alkylene, phenylene and C₁-C₉ alkylsubstituted phenylene. Non-limiting examples of straight or branchedchain alkylene can include but are not limited to methylene, ethylene,1,3-propylene, 1,2-propylene, 1,4-butylene, 1,2-butylene, pentylene,hexylene, heptylene, octylene, nonylene, decylene, undecylene,octadecylene and icosylene. Non-limiting examples of cyclic alkylenescan include but are not limited to cyclopentylene, cyclohexylene,cycloheptylene, cyclooctylene, and alkyl-substituted derivativesthereof. The divalent linking groups R₁ and R₂ can be chosen frommethylene, ethylene, phenylene, and alkyl-substituted phenylene, such asmethyl, ethyl, propyl, isopropyl and nonyl substituted phenylene.

In particular embodiments, the compound (a) having at least two thiolfunctional groups may be prepared by reacting together (1) any of thedithiols mentioned above, and (2) a compound having at least two doublebonds (for example, a diene). Such compounds having at least two doublebonds are described in more detail below, as are reaction methods.

The compound (b) having triple bond functionality used to prepare theoligomeric polythiol used in the present invention may comprise anyalkyne known to those skilled in the art. In certain embodiments, thealkyne comprises a hydroxyl functional alkyne, such as any of thoseknown in the art. Because a triple bond can react twice with a thiolfunctional group, for the purposes of the present invention, a triplebond is understood to be equal to two equivalents of a double bond whendetermining reaction stoichiometry.

Suitable non-limiting examples of hydroxyl functional compounds havingtriple bond functionality include propargyl alcohol, 2-butyne-1,4-diol,3-butyne-2-ol, 3-hexyne-2,5-diol, and/or mixtures thereof. A portion ofthe hydroxyl functional groups on the compound (b) may be esterified.For example, a portion of the compound (b) may comprise analkyne-functional ester of a C₁-C₁₂ carboxylic acid such as propargylacetate, propargyl propionate, propargyl benzoate, and the like.

In the preparation of the oligomeric polythiol used in certainembodiments of the present invention, the ratio of thiol functionalgroups in compound (a) to triple bonds in compound (b) typically rangesfrom 1.01:1 to 2.0:1, such as 1.5:1 to 2.0:1.

To prepare the oligomeric polythiols used in certain embodiments of thepresent invention, the reaction of the compound (a) with triplebond-containing compounds (b) can be carried out in the presence ofradical initiator. Suitable radical initiators for use in the presentinvention can vary widely and can include those known to one of ordinaryskill in the art. Non-limiting examples of radical initiators caninclude but are not limited to azo or peroxide type free-radicalinitiators such as azobisalkalenenitriles. The free-radical initiatorcan be azobisalkalenenitrile, which is commercially available fromDuPont in their VAZO line. VAZO, VAZO-52, VAZO-64, VAZO-67, VAZO-88 andmixtures thereof can also be used as radical initiators, for example.

Selection of the free-radical initiator can depend on reactiontemperature. The reaction temperature can vary, for example, from roomtemperature to 100° C. VAZO 52 can be used at a temperature of from50-60° C. VAZO 64 and VAZO 67 can be used at a temperature of 60-70° C.,and VAZO 88 can be used at a temperature of 70-100° C.

The amount of free radical initiator used in the reaction of the presentinvention can vary widely and can depend on the free radical initiatorselected. Typically, the free radical initiator is present in an amountof from 0.01% by weight to 5% by weight of the reaction mixture.

The reaction of the compound (a) with the triple bond-containingcompound (b) can be carried out under a variety of reaction conditions.Such conditions can depend on the degree of reactivity of the triplebond containing compound and the desired structure of the resultingpolythiol oligomer. In one reaction scheme, the reactants and a radicalinitiator can be combined together while heating the mixture.Alternatively, the triple bond containing-compound can be added inrelatively small amounts over a period of time to a mixture of polythioland radical initiator at a certain temperature. Also, the triple bondcontaining-compound can be combined with the compound (a) having atleast two thiol functional groups in a stepwise manner under radicalinitiation.

Certain embodiments of the present invention are further directed to useof a thioether-functional polythiol prepared by reacting together:

(a) a compound having at least two thiol functional groups as describedabove;

(b) a compound having triple bond functionality as described above; and

(c) a compound having at least two double bonds.

In certain embodiments, the compound having triple bond functionalitywill be a hydroxyl functional compound, so the polythiol will havependant hydroxyl functional groups.

The compound (a) having at least two thiol functional groups may be anythioether-functional, oligomeric polythiol, including those describedabove. In certain embodiments, the compound (a) comprises a reactionproduct of (1) any of the dithiols mentioned above, and (2) a compoundhaving at least two double bonds, which may be the same as or differentfrom the compound (c). The compound (b) having triple bond functionalitycan be any such compound, including those described above.

The compound (c) having at least two double bonds can be chosen fromnon-cyclic dienes, including but not limited to straight chain and/orbranched aliphatic non-cyclic dienes, non-aromatic ring-containingdienes, including non-aromatic ring-containing dienes wherein the doublebonds can be contained within the ring or not contained within the ringor any combination thereof, and wherein the non-aromatic ring-containingdienes can contain non-aromatic monocyclic groups or non-aromaticpolycyclic groups or combinations thereof; aromatic ring-containingdienes; or heterocyclic ring-containing dienes; or dienes containing anycombination of such non-cyclic and/or cyclic groups. The dienes canoptionally contain thioether, disulfide, polysulfide, sulfone, ester,thioester, carbonate, thiocarbonate, urethane, or thiourethane linkages,or halogen substituents, or combinations thereof; with the proviso thatthe dienes contain at least some double bonds capable of undergoingreaction with SH groups of a polythiol, and forming covalent C—S bonds.In certain embodiments the compound (c) having at least two double bondscomprises a mixture of dienes that are different from one another.

The compound (c) having at least two double bonds may comprise acyclicnon-conjugated dienes, acyclic polyvinyl ethers, allyl-(meth)acrylatesvinyl-(meth)acrylates, di(meth)acrylate esters of diols,di(meth)acrylate esters of dithiols, di(meth)acrylate esters ofpoly(alkyleneglycol) diols, monocyclic non-aromatic dienes, polycyclicnon-aromatic dienes, aromatic ring-containing dienes, diallyl esters ofaromatic ring dicarboxylic acids, divinyl esters of aromatic ringdicarboxylic acids, and/or mixtures thereof.

Non-limiting examples of acyclic non-conjugated dienes can include thoserepresented by the following formula IX:

wherein R₃ can represent C₁ to C₃₀ linear or branched divalent saturatedalkylene radical, or C₂ to C₃₀ divalent organic radical including groupssuch as but not limited to those containing ether, thioether, ester,thioester, ketone, polysulfide, sulfone and combinations thereof. Theacyclic non-conjugated dienes can be selected from 1,5-hexadiene,1,6-heptadiene, 1,7-octadiene and mixtures thereof.

Non-limiting examples of suitable acyclic polyvinyl ethers can includethose represented by the following formula X:

CH₂═CH—O—(—R₄—O—)_(m″)—CH═CH₂  (X)

wherein R₄ can be C₂ to C₆ n-alkylene, C₃ to C₆ branched alkylene group,or —[(CH₂—)_(p″)—O—]_(q″)—(—CH₂—)_(r′)—, m″ can be a rational numberfrom 0 to 10, often 2; p″ can be an integer from 2 to 6, q″ can be aninteger from 1 to 5 and r′ can be an integer from 2 to 10.

Non-limiting examples of polyvinyl ether monomers suitable for use caninclude but are not limited to divinyl ether monomers, such as ethyleneglycol divinyl ether, diethylene glycol divinyl ether, triethyleneglycoldivinyl ether, and mixtures thereof.

Di(meth)acrylate esters of linear diols can include but are not limitedto ethanediol di(meth)acrylate, 1,3-propanediol dimethacrylate,1,2-propanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate,1,3-butanediol di(meth)acrylate, 1,2-butanediol di(meth)acrylate, andmixtures thereof.

Di(meth)acrylate esters of dithiols can include but are not limited todi(meth)acrylate of 1,2-ethanedithiol including oligomers thereof,di(meth)acrylate of dimercaptodiethyl sulfide (2,2′-thioethanedithioldi(meth)acrylate) including oligomers thereof, di(meth)acrylate of3,6-dioxa-1,8-octanedithiol including oligomers thereof,di(meth)acrylate of 2-mercaptoethyl ether including oligomers thereof,di(meth)acrylate of 4,4′-thiodibenzenethiol, and mixtures thereof.

Further non-limiting examples of suitable dienes can include but are notlimited to monocyclic aliphatic dienes such as those represented byfollowing graphic formula XI:

wherein X′ and Y″ each independently can represent C₁₋₁₀ divalentsaturated alkylene radical; or C₁₋₅ divalent saturated alkylene radical,containing at least one element selected from the group of sulfur,oxygen and silicon in addition to the carbon and hydrogen atoms; and R₅can represent H, or C₁-C₁₀ alkyl; and those represented by the followinggraphic formula XII:

wherein X′ and R₅ can be as defined above and R₆ can represent C₂-C₁₀alkenyl. The monocyclic aliphatic dienes can include 1,4-cyclohexadiene,4-vinyl-1-cyclohexene, dipentene and terpinene.

Non-limiting examples of polycyclic aliphatic dienes can include5-vinyl-2-norbornene; 2,5-norbornadiene; dicyclopentadiene and mixturesthereof.

Non-limiting examples of aromatic ring-containing dienes can include butare not limited to those represented by the following graphic formulaXIII:

wherein R₇ can represent hydrogen or methyl. Aromatic ring-containingdienes can include monomers such as diisopropenyl benzene, divinylbenzene and mixtures thereof.

Examples of diallyl esters of aromatic ring dicarboxylic acids caninclude but are not limited to those represented by the followinggraphic formula XIV:

wherein each m′″ independently can be an integer from 0 to 5. Thediallyl esters of aromatic ring dicarboxylic acids can include o-diallylphthalate, m-diallyl phthalate, p-diallyl phthalate and mixturesthereof.

In certain embodiments, the compound (c) having at least two doublebonds comprises 5-vinyl-2-norbornene, ethylene glycol divinyl ether,diethylene glycol divinyl ether, triethylene glycol divinyl ether,butane diol divinyl ether, vinylcyclohexene, 4-vinyl-1-cyclohexene,dipentene, terpinene, dicyclopentadiene, cyclododecadiene,cyclooctadiene, 2-cyclopenten-1-yl-ether, 2,5-norbornadiene,divinylbenzene including but not limited to 1,3-divinylbenzene,1,2-divinylbenzene, and/or 1,4-divinylbenzene, diisopropenylbenzeneincluding but not limited to 1,3-diisopropenylbenzene,1,2-diisopropenylbenzene, and/or 1,4-diisopropenylbenzene, allyl(meth)acrylate, ethanediol di(meth)acrylate, 1,3-propanedioldi(meth)acrylate, 1,2-propanediol di(meth)acrylate, 1,3-butanedioldi(meth)acrylate, 1,2-butanediol di(meth)acrylate, ethylene glycoldi(meth)acrylate, diethylene glycol di(meth)acrylate,dimercaptodiethylsulfide di(meth)acrylate, 1,2-ethanedithioldi(meth)acrylate, and/or mixtures thereof.

Other non-limiting examples of suitable di(meth)acrylate monomers caninclude ethylene glycol di(meth)acrylate, 1,3-butylene glycoldi(meth)acrylate, 1,4-butanediol di(meth)acrylate,2,3-dimethyl-1,3-propanediol di(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycoldi(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropyleneglycol di(meth)acrylate, ethoxylated hexanediol di(meth)acrylate,propoxylated hexanediol di(meth)acrylate, neopentyl glycoldi(meth)acrylate, alkoxylated neopentyl glycol di(meth)acrylate,hexylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate,polyethylene glycol di(meth)acrylate, thiodiethyleneglycoldi(meth)acrylate, trimethylene glycol di(meth)acrylate, triethyleneglycol di(meth)acrylate, alkoxylated hexanediol di(meth)acrylate,alkoxylated neopentyl glycol di(meth)acrylate, pentanedioldi(meth)acrylate, cyclohexane dimethanol di(meth)acrylate, andethoxylated bis-phenol A di(meth)acrylate and/or mixtures thereof.

In the preparation of the oligomeric polythiol used in certainembodiments of the present invention, the reactants (a), (b), and (c)may all be reacted together simultaneously (as in a “one pot” process)or mixed together incrementally in various combinations. For example,compound (a) may be reacted first with the compound (b) having triplebond functionality as discussed above in a first reaction vessel toproduce a first reaction product, followed by addition of the compound(c) having at least two double bonds to the reaction mixture to reactwith the first reaction product and yield the oligomeric polythiol ofthe present invention (or addition of the first reaction product to asecond reaction vessel containing the compound (c)). As an alternative,the compound (a) may be reacted first with the compound (c) having atleast two double bonds to produce a first reaction product, followed byaddition of the compound (b) to yield the oligomeric polythiol. In thisembodiment, one may optionally add, simultaneously with or aftercompound (b), an additional compound (c) having at least two doublebonds, which may be the same as or different from that reacted earlierwith compound (a) to form the first reaction product.

When the compound (a) is combined first with the compound (c), it isbelieved that they react via a thiol-ene type reaction of the SH groupsof (a) with double bond groups of (c) although the inventors do not wishto be bound by this mechanism. Such reactions may typically take placein the presence of a radical initiator as mentioned above, or in thepresence of a base catalyst, particularly when the compound (c)comprises a compound having at least one (meth)acrylate type doublebonds. Suitable base catalysts for use in this reaction can vary widelyand can be selected from those known in the art. Non-limiting examplescan include tertiary amine bases such as1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and N,N-dimethylbenzylamine.The amount of base catalyst used can vary widely, but typically it ispresent in an amount of from 0.001 to 5.0% by weight of the mixture of(a) and (c).

In certain embodiments, the thioether functional polythiol isoligomeric. As used herein, the terms “oligomer” and “oligomeric” andthe like are intended to refer to compounds prepared by additionpolymerization to yield a material having repeating units and having anumber average molecular weight (Mn) up to 5000, such as up to 2000,such as 200 to 1200. The number average molecular weight may bedetermined by gel permeation chromatography using a polystyrenestandard.

The stoichiometric ratio of the sum of the number of thiol equivalentsof all polythiols present (compound (a)) to the sum of the number ofequivalents of all double bonds present (including alkyne functionalityeffective as two double bond equivalents as discussed above) is greaterthan 1:1. In non-limiting embodiments, this ratio can be within therange of from greater than 1:1 to 3:1, or from 1.01:1 to 3:1, or from1.01:1 to 2:1, or from 1.05:1 to 2:1, or from 1.1:1 to 1.5:1, or from1.25:1 to 1.5:1. Any endpoints within these ranges can also be combined.

Various methods of reacting polyvinyl ether monomers and one or moredithiol materials are described in detail in U.S. Pat. No. 6,509,418B1,column 4, line 52 through column 8, line 25, which disclosure is hereinincorporated by reference. Various methods of reacting allyl sulfide anddimercaptodiethylsulfide are described in detail in WO 03/042270, page2, line 16 to page 10, line 7, which disclosure is incorporated hereinby reference. Various methods for reacting a dithiol and an aliphatic,ring-containing non-conjugated diene in the presence of free radicalinitiator are described in detail in WO/01/66623A1, from page 3, line 19to page 6, line 11, the disclosure of which is incorporated herein byreference.

In reacting the compounds (a) and (c), it may be advantageous to use oneor more free radical initiators. Non-limiting examples of suitable freeradical initiators can include azo compounds, such as azobis-nitrilecompounds such as but not limited to azo(bis)isobutyronitrile (AIBN);organic peroxides such as but not limited to benzoyl peroxide andt-butyl peroxide; inorganic peroxides and similar free-radicalgenerators.

Alternately, the reaction of compounds (a) and (c) can be effected byirradiation with ultraviolet light either with or without aphotoinitiating moiety.

The mixture of (a) and (c) can be reacted for a time period of from 1hour to 5 days and at a temperature of from 20° C. to 100° C. Often, themixture is heated until a predetermined theoretical value for SH contentis achieved.

The stoichiometric ratio of the sum of the number of equivalents oftriple bond functional groups in compound (b) to the sum of the numberof equivalents of double bonds in compound (c) is often within the rangeof from 0.01:0.99 to 1.00:0, or from 0.10:0.90 to 1.00:0, or from0.20:0.80 to 1.00:0. Any endpoints within these ranges can also becombined.

As noted above the present sulfur-containing compounds can comprise apolythioether or a polymer comprising at least one polythioetherlinkage; that is, —[—CH₂—S—CH₂—]—. Typical polythioethers have from 8 to200 of these linkages. Polythioethers suitable for use in the presentinvention include but are not limited to those described in U.S. Pat.Nos. 6,372,849, 6,172,179, and 5,912,319, incorporated by referenceherein. Suitable polythioethers typically have a number averagemolecular weight of 150 to 10,000, such as 1,000 to 10,000, 2,000 to5,000 or 3,000 to 4,000. Any endpoints within these ranges can also becombined. In some embodiments, the polythioether component will beterminated with non-reactive groups, such as alkyl, and in otherembodiments will contain reactive groups in terminal or pendantpositions. Typical reactive groups are thiol, hydroxyl, amino, vinyl,and epoxy. For a polythioether component that contains reactivefunctional groups, the average functionality typically ranges from 2.05to 3.0, such as from 2.1 to 2.6. A specific average functionality can beachieved by suitable selection of reactive ingredients. Examples ofsuitable polythioethers are available from PRC-DeSoto International,Inc., in their PERMAPOL line, such as PERMAPOL P-3.1e and PERMAPOL P-3.

In certain embodiments, the sulfur-containing compound isdimercaptodioxaoctane (“DMDO”), and in certain specific embodiments thesulfur-containing compound is a trimer of DMDO. The trimer can beprepared as described in the examples below. In yet other embodiments,the sulfur-containing compound is a dimercaptan terminatedpolythioether, such as those described in U.S. patent application Ser.No. 11/260,553, incorporated by reference herein.

The sulfur-containing compound in the present invention can alsocomprise a polysulfide. A polysulfide is a polymer that containsmultiple sulfur-sulfur linkages; that is, —[S—S]—, in the polymerbackbone and/or in terminal or pendant positions on the polymer chain.In certain embodiments, the polysulfide polymers used according to thepresent invention have two or more sulfur-sulfur linkages. Suitablepolysulfides are commercially available from AKZO Nobel under the nameTHIOPLAST and from Toray Chemicals under the name THIOKEL. Theseproducts are available in a wide range of molecular weights ranging, forexample, from less than 1100 to over 8000, with molecular weight beingthe average molecular weight in grams per mole. Particularly suitable isa number average molecular weight of 1000 to 4000. The crosslink densityof these products also varies, depending on the amount of crosslinkingagent used. The mercaptan content, that is the “SH” content, of theseproducts can also vary. In some embodiments, it may be desired to use acombination of polysulfides to achieve the desired molecular weightand/or crosslink density in the present compositions. Differentmolecular weights and/or crosslink densities can contribute differentcharacteristics to the composition. For example, compositions whereinthe sulfur-containing compound comprises more than one polysulfidepolymer, and one of the polysulfide polymers has a molecular weight ofapproximately 1000, may have desirable non-crystallization properties.

In certain embodiments, the sulfur-containing compound is in the form ofa prepolymer. Such prepolymers can be prepared, for example, by reactinga thiol with a compound comprising isocyanate functionality; the thiolcan have one or more thiol groups and can further comprise one or moredisulfide linkages. Such prepolymers can be added to the isocyanatecomponent and/or the amine component.

When the second or amine component used in the formation of the presentcompositions comprises a sulfur-containing compound, the relative amountof the amine portion and the sulfur-containing compound portion can varydepending on the needs of the user. For example, the ratio of amine tosulfur-containing compound can vary from 1:99 to 99:1, and the aminecomponent can comprise ≧20 weight percent, ≧30 weight percent, or ≧35weight percent sulfur-containing compound, with weight percent based onthe total weight of the amine component.

In an embodiment, the coating compositions of the present invention mayfurther include polyurethane and/or poly(thio)urethane. It will beappreciated by those skilled in the art that polyurethane and/orpoly(thio)urethane can be formed as a by-product in the reactions of thepresent invention. In alternate embodiments, the polyurethane and/orpoly(thio)urethane can be formed in-situ and/or it can be added to thereaction mixture; a non-limiting example is an NCO functional prepolymerformed by reaction of a polyol and a polyisocyanate as disclosed herein.A non-limiting example of polyurethane formed in-situ may include thereaction product of polyisocyanate and hydroxyl-functional material, anda non-limiting example of poly(thio)urethane formed in-situ may includethe reaction product of polyisocyanate and polythioether or othersulfur-containing compound. Non-limiting examples of suitablepolyisocyanates may include those described herein. Non-limitingexamples of suitable hydroxyl-functional material may include polyolssuch as those described herein. Non-limiting examples ofsulfur-containing compounds may include those described herein. Anotherexample of polyurethane/poly(thio)urethane formed in-situ may includethe reaction product of hydroxyl functional prepolymer/thiol functionalprepolymer and isocyanate-functional material. Suitable examples ofthese reactants may include those described herein.

The polyurea/polythiourea coating composition of the present inventionmay be formulated and applied using various techniques known in the art.Accordingly, the present invention is further directed to methods forcoating a substrate comprising applying to at least a portion of thesubstrate any of the coating compositions described herein. In anembodiment, conventional spraying techniques may be used. In thisembodiment, the isocyanate component and amine component may be combinedsuch that the ratio of equivalents of isocyanate groups to equivalentsof amine/thiol groups is greater than 1 and the isocyanate component andthe amine component can be applied to a substrate at a volume mixingratio of 1:1; the reaction mixture may be applied to an uncoated orcoated substrate to form a first coating on the uncoated substrate or asubsequent coating on the coated substrate. When determining the ratioof equivalents of isocyanate groups to equivalents of reactiveamine/thiol groups, the total amine/thiol groups are taken intoconsideration; that is the amine groups from any amine or amines used inthe coating, and the thiol groups from any sulfur-containing compoundused in the coating.

It will be appreciated that the present compositions are two componentor “2K” compositions, wherein the isocyanate component and the aminecomponent are kept separate until just prior to application. Suchcompositions will be understood as curing under ambient conditions,although a heated forced air or a heat cure can be applied to acceleratefinal cure or to enhance coating properties such as adhesion. In anembodiment, the sprayable coating composition may be prepared using atwo-component mixing device. In this embodiment, isocyanate componentand amine component are added to a high pressure impingement mixingdevice. The isocyanate component is added to the “A-side” and aminecomponent is added to the “B-side”. The A- and B-side streams areimpinged upon each other and immediately sprayed onto at least a portionof an uncoated or coated substrate. The isocyanate and the amine or theamine and sulfur-containing compound react to produce a coatingcomposition that is cured upon application to the uncoated or coatedsubstrate. The A- and/or B-side can also be heated prior to application,such as to a temperature of 140° F. Heating may promote a betterviscosity match between the two components and thus better mixing, butis not necessary for the curing reaction to occur.

It is believed that the ratio of equivalents of isocyanate groups toamine/thiol groups may be selected to control the rate of cure of thecoating composition of the present invention. It has been found thatcure and adhesion advantages may result when applying the coating in a1:1 volume ratio wherein the ratio of the equivalents of isocyanategroups to amine/thiol groups (also known as the reaction index) isgreater than one, such as from 1.01 to 1.10:1, or from 1.03 to 1.10:1,or from 1.05 to 1.08:1 or from 1.01 to 1.4 to 1 or from 1.01 to 1.5, orgreater than 1.3 to 1. For example, good adhesion can be obtained usingthese ratios over clearcoats that have low surface functionality aftercure, such as carbamate melamine, hydroxyl melamine, 2K urethane, andsilane-containing clearcoats. The term “1:1 volume ratio” means that thevolume ratio varies by up to 20% for each component, or up to 10% or upto 5%.

The rate of reaction of the thiol groups with the isocyanate can bealtered depending on the type of amine or amines used. The amineco-reactant can function as a catalyst in the thiol/isocyanate reaction.While the inventors do not wish to be bound by any mechanism, it isbelieved that the greater the basicity of the amine, the faster the curerate between the thiol and the isocyanate. Accordingly, the particularamine used and the amount of the amine used can be altered to adjust thecure rate of the overall composition. Alternatively, a catalyst can beused to increase the reaction rate. Suitable catalysts include, forexample, DBU and other tertiary amines.

In a non-limiting embodiment, a commercially available mixing deviceavailable commercially under the designation GUSMER VR-H-3000proportioner fitted with a GUSMER Model GX-7 spray gun may be used. Inthis device, pressurized streams of the A- and B-side components aredelivered from two separate chambers and are impacted or impinged uponeach other at high velocity to mix the two components and form a coatingcomposition, which may be applied to an uncoated or coated substrateusing the spray gun. The mixing forces experienced by the componentstreams may depend upon the volume of each stream entering the mixingchamber per unit time and the pressure at which the component streamsare delivered. A 1:1 volume ratio of the isocyanate and amine/thiol perunit time may equalize these forces.

Another suitable application device known in the industry includes a“static mix tube” applicator. In this device, the isocyanate componentand amine component are each stored in a separate chamber. As pressureis applied, each of the components is brought into a mixing tube in a1:1 ratio by volume. Mixing of the components is effected by way of atorturous or cork screw pathway within the tube. The exit end of thetube may have atomization capability useful in spray application of thereaction mixture. Alternatively, the fluid reaction mixture may beapplied to a substrate as a bead. A static mix tube applicator iscommercially available from Cammda Corporation.

The polyurea/polythiourea coating compositions of the present inventionmay be applied to a wide variety of substrates. Accordingly, the presentinvention is further directed to a substrate coated with any of thecomposition described herein. Non-limiting examples of suitablesubstrates can include but are not limited to metal, natural and/orsynthetic stone, ceramic, glass, brick, cement, concrete, cinderblock,wood and composites and laminates thereof; wallboard, drywall,sheetrock, cement board, plastic, paper, PVC, roofing materials such asshingles, roofing composites and laminates, and roofing drywall,styrofoam, plastic composites, acrylic composites, ballistic composites,asphalt, fiberglass, soil, gravel and the like. Metals can include butare not limited to aluminum, cold rolled steel, electrogalvanized steel,hot dipped galvanized steel, titanium and alloys; plastics can includebut are not limited to TPO, SMC, TPU, polypropylene, polycarbonate,polyethylene, polyamides (Nylon). The substrates can be primed metaland/or plastic; that is, an organic or inorganic layer is appliedthereto. Further, the coating compositions of the present invention canbe applied to said substrates to impart one or more of a wide variety ofproperties such as but not limited to corrosion resistance, abrasionresistance, impact damage, flame and/or heat resistance, chemicalresistance, UV light resistance, structural integrity, ballisticmitigation, blast mitigation, sound dampening, decoration and the like.In non-limiting examples, the coating compositions of the presentinvention can be applied to at least a portion of a building structureor an article of manufacture such as but not limited to a vehicle.“Vehicle” includes but is not limited to civilian, commercial, andmilitary land-, water-, and air-vehicles, for example, cars, trucks,boats, ships, submarines, airplanes, helicopters, humvees and tanks. Thearticle of manufacture can be a building structure. “Building structure”includes but is not limited to at least a portion of a structureincluding residential, commercial and military structures, for example,roofs, floors, support beams, walls and the like. As used herein, theterm “substrate” may refer to a surface, either external or internal, onat least a portion of an article of manufacture or the article ofmanufacture itself. In an embodiment, the substrate is a truck bed.

In an embodiment, the polyurea/polythiourea coating composition of thepresent invention may be applied to a carrier film. The carrier film canbe selected from a wide variety of such materials known in the art.Non-limiting examples of suitable carrier films may include, but are notlimited to thermoplastic materials, thermosetting materials, metalfoils, cellulosic paper, synthetic papers, and mixtures thereof. As usedherein, the term “thermoplastic material” refers to any material that iscapable of softening or fusing when heated and of solidifying(hardening) again when cooled. Non-limiting examples of suitablethermoplastic materials may include polyolefins, polyurethanes,polyesters, polyamides, polyureas, acrylics, and mixtures thereof. Asused herein, the term “thermosetting material” refers to any materialthat becomes permanently rigid after being heated and/or cured.Non-limiting examples may include polyurethane polymers, polyesterpolymers, polyamide polymers, polyurea polymers, polycarbonate polymers,acrylic polymers, aminoplasts, isocyanates, epoxies, copolymers thereof,and mixtures thereof.

As noted above, in certain embodiments, the polyurea/polythioureacoating compositions of the present invention may be applied to a bare(e.g., untreated, uncoated) substrate, a pretreated substrate and/orcoated substrate having at least one other coating. In a non-limitingembodiment, the coating compositions of the present invention may beapplied as part of a multi-layer coating composite. The first coatingapplied to a substrate may be selected from a variety of coatingcompositions known in the art for surface coating substrates.Non-limiting examples may include but are not limited toelectrodepositable film-forming compositions, primer compositions,pigmented or non-pigmented monocoat compositions, pigmented ornon-pigmented base coat compositions, transparent topcoat compositions,industrial coating compositions, and the like. In another non-limitingembodiment, the coating compositions of the present invention may beapplied as part of a multi-layer coating composite comprising apretreated substrate and coating layers such as but not limited toelectrocoat, primer, base coat, clear coat, and combinations thereof. Inan embodiment, the clear coat comprises silane functional groups eitherbefore or after crosslinking and cure.

In a further embodiment, the polyurea/polythiourea coating compositionsof the present invention can be used in a two-coat application resultingin a textured surface. A first coat is applied to an uncoated or coatedsubstrate to produce a smooth, substantially tack-free layer. The“Tack-Free Method” is used to determine if the layer is substantiallytack-free. The Tack-Free Method includes spraying the coatingcomposition in one coat onto a non-adhering plastic sheet to a thicknessof from 10 to 15 mil (254-381 microns). When spraying is complete, anoperator, using a loose fitting, disposable vinyl glove, such as onecommercially available as AMBIDEX Disposable Vinyl Glove by MarigoldIndustrial, Norcross Ga., gently touches the surface of the coating. Thecoating may be touched more than one time by using a differentfingertip. When the glove tip no longer sticks to, or must be pulledfrom, the surface of the layer, the layer is said to be substantiallytack-free. The time beginning from the completion of spraying until whenthe coating is substantially tack-free is said to be the tack time ortack-free time. In a non-limiting embodiment, the tack-free time and thecure time may be controlled by balancing levels of various compositioncomponents such as the amount and/or type of amine.

A second coat may then be applied to the first coating layer as atexturizing layer or “dust coating”. The second coating layer can beapplied by increasing the distance between the application/mixing deviceand the coated substrate to form discrete droplets of the coatingcomposition prior to contacting the coated substrate thereby formingcontrolled non-uniformity in the surface of the second layer. Thesubstantially tack-free first layer of the coating is at least partiallyresistant to the second layer; i.e., at least partially resistant tocoalescence of the droplets of coating composition sprayed thereon asthe second layer or dust coating such that the droplets adhere to but donot coalesce with the previous layer(s) to create surface texture. Thefinal coating layer typically exhibits more surface texture than thefirst or previous coating layers. Alternatively, a textured surface maybe achieved by injection during in-mold coating, or by spray coating thepresent composition and then rolling a texture onto its surface. Anoverall thickness of the coating layers may range from 20 to 1000 mils,or from 40 to 150 mils, or from 60 to 100 mils (1524-2540 microns), orfrom 500 to 750 mils. Any of the endpoints within these ranges can alsobe combined. In a non-limiting embodiment, the first layer may be themajority of the total thickness and the dust coating may be from 15-50mils (381-1270 microns).

In various embodiments of the present invention, the “first” coatinglayer may comprise one, two, three or more layers; and the “second”coating layer may be one or more subsequent layers applied thereover.For example, four polyurea (or polyurea/polythiourea) layers may beapplied, with the fourth layer being the dust coating and each layerhaving a thickness of from 15 to 25 mil (381-635 microns). It will beappreciated that these coating layers are relatively “thick”. Thecoating compositions of the present invention can also be applied asmuch thinner layers as well, such as 0.1 to less the 15 mils, such as0.1 to 10, 0.5 to 3 or 1 to 2 mils. Any of the endpoints within theseranges can also be combined. Such layers can be used alone or inconjunction with other coating layers, such as any of those known in theart or otherwise described herein. When applied at a sufficientthickness (e.g. 10 to 1000 mils, such as 100 to 200 mils, or 125mils+/−10 mils), the present polyurea/polythiourea layer(s) can provideblast and/or ballistic mitigation. “Blast and/or ballistic mitigation”means, for example, protection in the event of a close proximity blast,projectile, or explosion. This protection can include, for example,protection of a structure or portion of a structure, such as a buildingstructure, vehicle, aircraft, ship/boat, shipping container and thelike, from collapse and/or destruction, protection against flying debrisand blast fragments, gunshots and the like.

In alternate embodiments, the coating layers may comprise the same ordifferent polyurea/polythiourea coating compositions. For example, thefirst layer may be a composition comprising aliphatic and/or aromaticamine components and/or aliphatic and/or aromatic polyisocyanate and thesecond layer may comprise the same or different combination of aliphaticand/or aromatic amine components and/or aliphatic and/or aromaticpolyisocyanate. Either or both layers may further comprise any of thesulfur-containing compounds described herein. “Amine component” in thiscontext means any amine used in the present coatings. In a furtherembodiment, the outermost coating layer may comprise a coatingcomposition that provides a desired durability. The desired durabilitymay depend upon the use of the coating composition of the presentinvention and/or the substrate to which it may be applied. In anembodiment, a combination of aliphatic and/or aromatic amine and/orpolyisocyanate may be selected such that the composition of theoutermost layer has substantial durability. For example, the outermostcoating layer may have a durability of 1000 kJ to 6000 kJ, or from 800hours to 4000 hours, when tested using a Weatherometer (Atlas MaterialTesting Solutions) in accordance with method SAE J1960. In thisembodiment, the first layer may be a polyurea composition comprisingpolyisocyanate and amine, wherein at least one of the amine and/orpolyisocyanate may comprise an aromatic moiety, and the second layer maybe a polyurea composition comprising predominantly aliphatic amine andaliphatic polyisocyanate, with little or no aromaticity; again, eitheror both of the layers can further comprise any of the sulfur-containingcompounds described herein.

The polyurea/polythiourea coating compositions of the present inventionmay optionally include materials standard in the art such as but notlimited to fillers, fiberglass, stabilizers, thickeners, fillers,adhesion promoters, catalysts, colorants, antioxidants, UV absorbers,hindered amine light stabilizers, rheology modifiers, flow additives,anti-static agents and other performance or property modifiers that arewell known in the art of surface coatings, and mixtures thereof. Forexample, the present coatings can further comprise flame and/or heatresistant material, such as any one or more of those disclosed in U.S.application Ser. No. 11/460,439, hereby incorporated by reference in itsentirety. Fillers can include clay and/or silica, and adhesion promoterscan include amine functional materials, aminosilanes and the like;examples of fillers and adhesion promoters are further described in U.S.Publication No. 2006/0046068 and U.S. application Ser. No. 11/591,312,hereby incorporated by reference in their entirety. These additives canbe combined with the isocyanate component, the amine component, or both.In certain embodiments, the coating may further comprise small amountsof solvent and in certain embodiments the coating may be substantiallysolvent-free. “Substantially solvent-free” means that the coating maycontain a small amount of solvent, such as 5%, 2%, 1% or less.

The coatings of the present invention can also include a colorant. Asused herein, the term “colorant” means any substance that imparts colorand/or other opacity and/or other visual effect to the composition. Thecolorant can be added to the coating in any suitable form, such asdiscrete particles, dispersions, solutions and/or flakes. A singlecolorant or a mixture of two or more colorants can be used in thecoatings of the present invention.

Example colorants include pigments, dyes and tints, such as those usedin the paint industry and/or listed in the Dry Color ManufacturersAssociation (DCMA), as well as special effect compositions. A colorantmay include, for example, a finely divided solid powder that isinsoluble but wettable under the conditions of use. A colorant can beorganic or inorganic and can be agglomerated or non-agglomerated.Colorants can be incorporated into the coatings by grinding or simplemixing. Colorants can be incorporated by grinding into the coating byuse of a grind vehicle, such as an acrylic grind vehicle, the use ofwhich will be familiar to one skilled in the art.

Example pigments and/or pigment compositions include, but are notlimited to, carbazole dioxazine crude pigment, azo, monoazo, disazo,naphthol AS, salt type (lakes), benzimidazolone, condensation, metalcomplex, isoindolinone, isoindoline and polycyclic phthalocyanine,quinacridone, perylene, perinone, diketopyrrolo pyrrole, thioindigo,anthraquinone, indanthrone, anthrapyrimidine, flavanthrone, pyranthrone,anthanthrone, dioxazine, triarylcarbonium, quinophthalone pigments,diketo pyrrolo pyrrole red (“DPPBO red”), titanium dioxide, carbonblack, carbon fiber, graphite, other conductive pigments and/or fillersand mixtures thereof. The terms “pigment” and “colored filler” can beused interchangeably.

Example dyes include, but are not limited to, those that are solventand/or aqueous based such as acid dyes, azoic dyes, basic dyes, directdyes, disperse dyes, reactive dyes, solvent dyes, sulfur dyes, mordantdyes, for example, bismuth vanadate, anthraquinone, perylene, aluminum,quinacridone, thiazole, thiazine, azo, indigoid, nitro, nitroso,oxazine, phthalocyanine, quinoline, stilbene, and triphenyl methane.

Example tints include, but are not limited to, pigments dispersed inwater-based or water miscible carriers such as AQUA-CHEM 896commercially available from Degussa, Inc., CHARISMA COLORANTS andMAXITONER INDUSTRIAL COLORANTS commercially available from AccurateDispersions division of Eastman Chemical, Inc.

As noted above, the colorant can be in the form of a dispersionincluding, but not limited to, a nanoparticle dispersion. Nanoparticledispersions can include one or more highly dispersed nanoparticlecolorants and/or colorant particles that produce a desired visible colorand/or opacity and/or visual effect. Nanoparticle dispersions caninclude colorants such as pigments or dyes having a particle size ofless than 150 nm, such as less than 70 nm, or less than 30 nm.Nanoparticles can be produced by milling stock organic or inorganicpigments with grinding media having a particle size of less than 0.5 mm.Example nanoparticle dispersions and methods for making them areidentified in U.S. Pat. No. 6,875,800 B2, which is incorporated hereinby reference. Nanoparticle dispersions can also be produced bycrystallization, precipitation, gas phase condensation, and chemicalattrition (i.e., partial dissolution). In order to minimizere-agglomeration of nanoparticles within the coating, a dispersion ofresin-coated nanoparticles can be used. As used herein, a “dispersion ofresin-coated nanoparticles” refers to a continuous phase in which isdispersed discreet “composite microparticles” that comprise ananoparticle and a resin coating on the nanoparticle. Exampledispersions of resin-coated nanoparticles and methods for making themare identified in U.S. application Ser. No. 10/876,031 filed Jun. 24,2004, which is incorporated herein by reference, and U.S. ProvisionalApplication No. 60/482,167 filed Jun. 24, 2003, which is alsoincorporated herein by reference.

Example special effect compositions that may be used in the coating ofthe present invention include pigments and/or compositions that produceone or more appearance effects such as reflectance, pearlescence,metallic sheen, phosphorescence, fluorescence, photochromism,photosensitivity, thermochromism, goniochromism and/or color-change.Additional special effect compositions can provide other perceptibleproperties, such as reflectivity, opacity or texture. In a non-limitingembodiment, special effect compositions can produce a color shift, suchthat the color of the coating changes when the coating is viewed atdifferent angles. Example color effect compositions are identified inU.S. Pat. No. 6,894,086, incorporated herein by reference. Additionalcolor effect compositions can include transparent coated mica and/orsynthetic mica, coated silica, coated alumina, a transparent liquidcrystal pigment, a liquid crystal coating, and/or any compositionwherein interference results from a refractive index differential withinthe material and not because of the refractive index differentialbetween the surface of the material and the air.

In certain non-limiting embodiments, a photosensitive composition and/orphotochromic composition, which reversibly alters its color when exposedto one or more light sources, can be used in the coating of the presentinvention. Photochromic and/or photosensitive compositions can beactivated by exposure to radiation of a specified wavelength. When thecomposition becomes excited, the molecular structure is changed and thealtered structure exhibits a new color that is different from theoriginal color of the composition. When the exposure to radiation isremoved, the photochromic and/or photosensitive composition can returnto a state of rest, in which the original color of the compositionreturns. In one non-limiting embodiment, the photochromic and/orphotosensitive composition can be colorless in a non-excited state andexhibit a color in an excited state. Full color-change can appear withinmilliseconds to several minutes, such as from 20 seconds to 60 seconds.Example photochromic and/or photosensitive compositions includephotochromic dyes.

In a non-limiting embodiment, the photosensitive composition and/orphotochromic composition can be associated with and/or at leastpartially bound to, such as by covalent bonding, a polymer and/orpolymeric materials of a polymerizable component. In contrast to somecoatings in which the photosensitive composition may migrate out of thecoating and crystallize into the substrate, the photosensitivecomposition and/or photochromic composition associated with and/or atleast partially bound to a polymer and/or polymerizable component inaccordance with a non-limiting embodiment of the present invention, haveminimal migration out of the coating. Example photosensitivecompositions and/or photochromic compositions and methods for makingthem are identified in U.S. application Ser. No. 10/892,919 filed Jul.16, 2004 and incorporated herein by reference.

In general, the colorant can be present in the coating composition inany amount sufficient to impart the desired property, visual and/orcolor effect. The colorant may comprise from 1 to 65 weight percent ofthe present compositions, such as from 3 to 40 weight percent or 5 to 35weight percent, with weight percent based on the total weight of thecompositions.

In another embodiment, the polyurea/polythiourea coating compositions ofthe present invention when applied to a substrate possesses color thatmatches the color of an associated substrate. As used herein, the term“matches” or like terms when referring to color matching means that thecolor of the coating composition of the present invention substantiallycorresponds to a desired color or the color of an associated substrate.For instance, when the substrate for the polyurea coating composition isa portion of a vehicle, such as a truck bed, the color of the coatingsubstantially matches that of the associated vehicle body. This can bevisually observed, or confirmed using spectroscopy equipment.

The coatings of the present invention may be part of a multi-layercoating composite comprising a substrate with various coating layerssuch as a pretreatment layer, electrocoat, primer, base coat and clearcoat. At least one of the base coat and clear coat may contain pigmentand/or the clear coat may contain an adhesion promoter and any of thesecoatings can be one or more of the coatings described herein. It isbelieved that the addition of adhesion promoter to the clear coat, or toits surface, may improve the adhesion between the clear coat and thecoating composition applied thereover, although the inventors do notwish to be bound by any mechanism. In this embodiment, the coatingcomposition of the present invention may be the reaction product of theisocyanate component and the amine component with a colorant additive.The coating composition of the present invention containing colorant maybe applied to at least a portion of the article or structure. The colorof the coated article or structure may match the color of an associatedsubstrate. An “associated substrate” may refer to a substrate thatcomprises the article or structure but is not coated with the coatingcomposition of the present invention or a substrate that is attached,connected or in close proximity to the article or structure, but is notcoated with the coating composition of the present invention.

As used herein, unless otherwise expressly specified, all numbers suchas those expressing values, ranges, amounts or percentages may be readas if prefaced by the word “about”, even if the term does not expresslyappear. Any numerical range recited herein is intended to include allsub-ranges subsumed therein. Plural encompasses singular and vice versa.“Including” and like terms are open ended; that is, they mean “includingbut not limited to”. For example, while the invention has been describedherein including the claims in terms of “a” polyurea/polythiourea, “an”isocyanate, “an” amine, “a” sulfur-containing compound, “a” polythiol,“a” polythioether, “a” polysulfide, “a” catalyst, and the like, mixturesof all of such things can be used. Also, as used herein, the term“polymer” is meant to refer to prepolymers, oligomers and bothhomopolymers and copolymers; the prefix “poly” refers to two or more.

EXAMPLES

The following examples are intended to illustrate the invention andshould not be construed as limiting the invention in any way.

In the following examples, unless otherwise stated, the refractive indexand Abbe number were measured on a multiple wavelength AbbeRefractometer Model DR-M2 manufactured by ATAGO Co., Ltd.; therefractive index and Abbe number of liquids were measured in accordancewith ASTM-D1218; the refractive index and Abbe number of solids wasmeasured in accordance with ASTM-D-542.

The viscosity was measured using a Brookfield CAP 2000+Viscometer.

The SH equivalents were determined using the following procedure. Asample size (0.1 mg) of the product was combined with 50 mL oftetrahydrofuran (THF)/propylene glycol (80/20) and stirred at roomtemperature until the sample was substantially dissolved. Whilestirring, 25.0 mL of 0.1 N iodine solution (which was commerciallyobtained from Aldrich 31, 8898-1) was added to the mixture and thenallowed to react for a time period of from 5 to 10 minutes. To thismixture was added 2.0 mL concentrated HCl. The mixture was then titratedpotentiometrically with 0.1 N sodium thiosulfate in the millivolt (mV)mode. A blank value was initially obtained by titrating 25.0 mL iodine(including 1 mL of concentrated hydrochloric acid) with sodiumthiosulfate in the same manner as conducted with the product sample.

${\% \mspace{11mu} {SH}} = \frac{\begin{matrix}{( {{{mls}\mspace{11mu} {Blank}} - {{mls}\mspace{11mu} {Sample}}} ) \times ( {{Normality}\mspace{14mu} {NA}_{2}S_{2}O_{3}} ) \times} \\(3.307)\end{matrix}}{{{Sample}\mspace{14mu} {weight}},g}$

Example 1 Synthesis of 2/1 (mol/mol) Adduct of Dimercaptodiethylsulfide(DMDS) and Propargyl Alcohol (PA) (Polythiol H)

In a glass jar with magnetic stirrer were mixed DMDS from Nisso Maruzen,Japan, 154.0 g. (1.0 mol) and PA from Aldrich, 28.0 g. (0.5 mol) at roomtemperature. Then this mixture was heated up to 60° C. using an oilbath. The mixture was kept at this temperature while stirring for 30min. An exothermic reaction started to take place, leading to anincrease in the temperature of the reaction mixture to 80° C. for ashort period of time. This exothermic reaction was over after 30 minutesand the reaction temperature went down to 60° C., the temperature of theheating bath. Radical initiator VAZO¹ 64, 50 mg., 275 ppm was addedthree times at intervals of 5 hours while the mixture was stirred at 60°C. The equivalent weight of the product was 181.5 g/equiv (theoretical182 g/equiv), based on an Mn=363. VAZO 64, 50 mg., 275 ppm was addedagain and the mixture was heated at 60° C. upon stirring for another 5hours. The equivalent weight measurement showed no changes and thereaction was considered completed. The viscosity of the materials was258 cPs (25° C.), nD=1.627, Abbe 36, nE=1.631, Abbe 36. The yield wasquantitative. ¹ Available from DuPont.

Example 2 Synthesis of 2/1 (mol/mol) Adduct of (DMDS) and1,3-Diisopropenyl Benzene (DIPEB) (POLYTHIOL B)

524.6 g DMDS (3.4 mol) were charged to a glass jar, and the contentswere heated to 60° C. To the jar was slowly added 269.0 g DIPEB (1.7mol) with mixing. Once the addition of DIPEB was completed, the jar wasplaced in an oven heated to 60° C. for 2 hours. Afterwards, 0.1 g VAZO52 was dissolved into the contents of the jar, and the jar was returnedto the oven. After 20 hours, the resulting sample was titrated for —SHequivalents and was found to have an equivalent weight of 145 g/mol. 0.1g VAZO 52 was dissolved into the reaction mixture, which was thenreturned to the oven. Over the course of 8 hours, two additions of 0.2 gVAZO 52 were made, and the reaction mixture kept in the 60° C. oven overthat time frame. 17 hours after the final addition of VAZO 52 was made,the resulting sample was titrated to an equivalent weight of 238 g/equiv(theoretical 233 g/equivalent). The viscosity of the material at 25° C.was measured and found to be 490 cPs. The yield was quantitative.

Example 3 Synthesis of 2/1 (mol/mol) Adduct of POLYTHIOL B and PA(POLYTHIOL E)

Polythiol B (prepared according to Example 2) 200.0 g. (0.42 mol) andPA, 11.6 g. (0.21 mol) were mixed at room temperature. Then this mixturewas heated up to 65° C. Radical initiator VAZO 52, 42 mg, 200 ppm wasadded three times at intervals of 5 hours while the mixture was stirredat 65° C. The SH equivalent weight was determined to be 499 g/equiv. Themixture was heated at 65° C. for another 5 hours and the SH equivalentweight was measured again, and determined to be 499 g/equiv, based on anMn=998. The viscosity of the mixture was 463 cPs (73° C.), nD=1.620,Abbe 36, nE=1.624, Abbe 35. The yield was quantitative.

Example 4 Synthesis of 2/1 (mol/mol) Adduct of DMDS and5-Vinyl-2-norbornene (VNB) (POLYTHIOL V)

77 g DMDS (0.5 mol) was charged to a glass jar, and the contents wereheated to 60° C. To this jar was slowly added 30 g VNB (0.25 mol) withmixing, while keeping the temperature of the mixture ˜60° C. Aftercompletion of the addition the mixture was heated at 60° C. for another30 min, then 0.2 g VAZO 67 was dissolved into the contents of the jar,and the jar was heated at 65° C. for 20 hours. The resulting product wasanalyzed for SH content by titration with iodine. An SH equivalentweight of 216 g/equiv (theoretical 214 g/equivalent) was calculated. Theviscosity of the material at 25° C. was measured and found to be 460cPs. The product obtained was a transparent colorless liquid, nD=1.607,Abbe 39, n_(E)=1.610, Abbe 39. The yield was quantitative.

Example 5 Polythiol Blend

A polythiol blend was prepared by blending Polythiol B (prepared asdescribed in Example 2) and Polythiol E (prepared as described inExample 3) in a ratio of 3/2 (w/w) by weight.

Example 6 Dimercaptodioxaoctane (DMDO) Trimer

A thiol functional resin was prepared as described below:

Triallylcyanurate acid (167.8 g) and DMDO (371.81 g) were combined andwarmed to 65° C. and 0.1416 g of VAZO 67 added. The reaction wasmonitored hourly by measuring the thiol equivalent weight. VAZO 67(approx 0.15 g) was added after each measurement until the thiolequivalent weight was greater than 250 meq/g. After the initial 2 hoursthe temperature was increased to 85° C., and after an additional 2 hoursthe reaction temperature was increased to 95° C. The reaction wasmonitored for a total of 8 hours. The final material had a measuredsolids content of 95% (1 hr, 110° C.), thiol equivalent weight of 257meq/g and Mw of 5858 as measured by gel permeation chromatography. TheDMDO trimer thus prepared can be incorporated into a coating accordingto the present invention by using the trimer in the amine component asgenerally taught herein. Alternatively the DMDO trimer can be formulatedinto a prepolymer and used in the isocyanate component.

Examples 7-12

An isocyanate-functional polythiourethane for use as the “A” side inExample 12 was prepared as described below:

A total of 193.6 grams of isophorone diisocyanate, 180 grams ofTHIOPLAST G4², and 136.8 grams of TERATHANE 6503, were added to asuitable reaction vessel equipped with a stirrer, temperature probe,condenser and a nitrogen cap. The contents of the flask were mixed well.Then 0.3 grams of dibutyltin dilaurate were added to the mixture. Thecontents were slowly heated to 80° C. The contents underwent an exothermto 112° C. The reaction was held at 100° C. for 2.5 hours. Theisocyanate equivalent weight of the contents was then measured and foundto be 537. The temperature of the reaction mixture was lowered to 80° C.Finally, 224 grams of DESMODUR⁴ XP2580 and 225 grams of DESMODUR⁵ XP2410were added to the reaction mixture. The contents of the reactor werecooled and poured out. The final material had a measured solids of 96%,a viscosity of Z3, and an isocyanate equivalent weight of 266.

percent by Component weight A-side For Example 12 IPDI 16.05 DBTDL 0.003TERATHANE 650 11.35 AKZO NOBEL G4 14.92 DESMODUR XP2410 28.84 DESMODURXP2580 28.84 ²Mercaptan-terminated poly-disulfide mixture, availablefrom AKZO Nobel. ³Polytetramethylene ether glycol, available fromInvista. ⁴An allophonate of hexamethylene diisocyanate, available fromBayer Material Science. ⁵An asymmetric trimer of hexamethylenediisocyanate, available from Bayer Material Science.

An isocyanate-functional polyurethane for use as the A side in Examples7-11, was prepared as described below:

A total of 1348.9 grams of isophorone diisocyanate (IPDI) and 1901.5grams of TERATHANE 650, were added to a suitable reaction vesselequipped with a stirrer, temperature probe, condenser and a nitrogencap. The contents of the flask were mixed well. Then 0.2 grams ofdibutyltin dilaurate (DBTDL) were added to the mixture. The contentswere slowly heated to 80° C. The contents underwent an exotherm to 112°C. The reaction was held at 100° C. for 2.5 hours. The isocyanateequivalent weight of the contents was then measured and found to be 531.The temperature of the reaction mixture was lowered to 80° C. Finally,2490.6 grams of DESMODUR XP2580 and 2490.6 grams of DESMODUR XP2410 wereadded to the reaction mixture. The contents of the reactor were cooledand poured out. The final material had a measured solids of 98%, aviscosity of Y, and an isocyanate equivalent weight of 255.8.

percent by Component weight A-side For Examples 7-11 IPDI 16.4 DBTDL0.003 TERATHANE 650 23.1 DESMODUR XP2410 30.3 DESMODUR XP2580 30.3

Pigment grinds were prepared according to the following table:

Grind 1 Ingredient Percent by Weight JEFFAMINE T3000⁶ 24.0 DESMOPHEN1220 NH⁷ 22 BYK-9077⁸ 0.6 VULCAN XC72⁹ 1.2 BENTONE 34¹⁰ 3⁶Polyoxyalkylene primary amine of approximately 3000 MW, available fromHuntsman Corporation. ⁷Amine-functional asparatic acid ester, availablefrom Bayer Corporation. ⁸Additive, available from Byk-Chemie. ⁹Carbonblack pigment, available from Cabot Corporation. ¹⁰Organoclay rheologyadditive, available from Elementis Specialities, Inc.For Grind 1, the ingredients were combined and charged to a ModelHM1.5VSD bead mill (Premier Mill Inc.) using with Mill Mates TZP Plusgrind media (supplied by Zircoa Inc) at 85% mill loading and ground at amill speed of 2400 rpm. The grinds were judged to be complete when theparticle size was found to be 7.5 Hegman upon drawdown on a fineness ofgrind gauge.

The “B” side formulations were prepared as shown in the following table:

percent by weight B-side Component Ex 7 Ex 8 Ex 9 Ex 10 Ex 11 Ex 12GRIND 1 50.8 50.8 50.8 50.8 50.8 50.8 JEFFAMINE T-3000 10 — — — — —JEFFLINK 754¹¹ — 29.7 17.5 23.1 19.7 29.2 DESMOPHEN 1220 NH 11 8 9 9 910 DMDO (95%)¹² — — — — 6 — POLYTHIOL H (from Example 1) 17 — — — — —POLYTHIOL V (from Example 4) — 9 — — — — POLYTHIOL B (from Example 2) —— 20.2 — — — POLYTHIOL BLEND (from — — — 14.60 — — Example 5) P3.1e¹³ —— — — 12 — CLEARLINK 1000¹⁴ 8.7 — — — — — CHISORB 353¹⁵ 2 2 2 2 2 2DABCO T-12 (dibutyl tin 0.5 0.5 0.5 0.5 0.5 0.5 dilaurate) ratio ofequivalents (Index) of 1.100 1.107 1.098 1.101 1.094 1.089 isocyanate toamine/thiol ¹¹Alicyclic secondary amine, available from HuntsmanCorporation. ¹²Available from Sigma-Aldrich, Inc. ¹³Polythioether,available from PRC-DeSoto International, Inc. ¹⁴Aliphatic secondaryamine, available from Drof-Ketal Chemicals, LLC. ¹⁵Hindered amine lightstabilizer, available from Chitec Chemical Corporation.

The B side formulations of the table above were made by taking Grind 1and then blending in the balance of the other materials until wellmixed. The B side formulations were charged into separate canisters andto be paired up with the A side formulation (in separate canisters) andheated to 140° F. in an oven for 2-6 hrs prior to spraying to ensuresamples were equilibrated. Polyurea coating compositions were producedby mixing a 1:1 volume ratio of the A-side components to the B-sidecomponents in a static mix tube applicator device available from CammdaCorporation and sprayed onto panels.

Hardness values were determined by charging the A and B side componentsinto a double-barreled syringe equipped with a static mix tube and a“Pneumatic applicator” (PC Cox Limited) and injecting the components ata 1:1 ratio into a mold to form a round “puck” of approximately 6 cm indiameter and 0.2 cm in thickness. The hardness of the polyurea coatingpuck at ambient temperature was measured on the Shore D scale with aModel 212 Pencil Style Digital Durometer (Pacific Transducer Corp.) Thepucks were then placed in a 140° F. oven for 1 day and the Shore Dhardness of the coating measured with the puck still inside the oven toprevent cooling. The pucks were removed from the oven and cooled toambient temperature. The hardness was measured again on those pucks atambient temperature after being out of the oven for 1 day.

The following table shows results of characterization of the resultingcoatings:

Ex 7 Ex 8 Ex 9 Ex 10 Ex 11 Ex 12 Tack free time (sec) 75   32   50  70   60   38   Hardness (Shore D) @ 55.2 68.3 53.8 64.2 59.2 64.2ambient temperature, 1 day ambient cure Hardness (Shore D) @ — — — —61.1 65.1 ambient temperature after 3 days ambient cure Hardness (ShoreD) @ 51.5 67.6 43.6 61.2 — — ambient temperature after 4 days ambientcure Hardness (Shore D) @ 52.8 62.2 44.3 60.5 60.5 67.1 ambienttemperature after 7 days ambient cure Hardness (Shore D) after 26.4 24.418.1 23.1 28.1 25.6 7 days at ambient temperature plus 1 day at 140° F.measure @ 140° F. Hardness (Shore D), 7 36.2 55.6 35.8 47.4 55.4 65.4days at ambient plus 1 day at 140° F., after 1 day ambient (recovery)measured @ ambient

Whereas particular embodiments of this invention have been describedabove for purposes of illustration, it will be evident to those skilledin the art that numerous variations of the details of the presentinvention may be made without departing from the invention as defined inthe appended claims.

1. A coating composition comprising polyurea and polythiourea formedfrom a reaction mixture comprising: a first component comprisingisocyanate; a second component comprising an amine; and asulfur-containing compound in the first and/or second component.
 2. Thecoating of claim 1, wherein the sulfur-containing compound is in thefirst component.
 3. The coating of claim 1, wherein thesulfur-containing compound is in the second component.
 4. The coatingcomposition of claim 3, wherein the ratio of equivalents of isocyanategroups to equivalents of amine and thiol groups is greater than 1 andthe first component and the second component can be applied to asubstrate at a volume mixing ratio of 1:1.
 5. The coating composition ofclaim 2, wherein the ratio of equivalents of isocyanate groups toequivalents of amine and thiol groups is 1.01-1.5:1.
 6. The coatingcomposition of claim 1, wherein the isocyanate comprises an isocyanateprepolymer.
 7. The coating composition of claim 1, wherein theisocyanate comprises an isophorone diisocyanate.
 8. The coatingcomposition of claim 1, wherein the amine comprises a polyamine.
 9. Thecoating composition of claim 8, wherein the polyamine comprisespolyoxyalkylene primary amine.
 10. The coating composition of claim 1,wherein the sulfur-containing compound comprises a polythiol.
 11. Thecoating composition of claim 10, wherein the polythiol comprises athioether functional polythiol prepared by reacting together: a) acompound having at least two thiol functional groups; and b) a compoundhaving triple bond functionality.
 12. The coating composition of claim9, wherein the compound having at least two thiol functional groupscomprises dimercaptodiethyl sulfide.
 13. The compound of claim 9,wherein the compound having triple bond functionality comprisespropargyl alcohol.
 14. The compound of claim 11, wherein the thioetherfunctional polythiol is further prepared by reacting: c) a compoundhaving at least two double bonds.
 15. The composition of claim 1,wherein the sulfur-containing compound comprises dimercaptodioxaoctane.16. The composition of claim 1, wherein the sulfur-containing compoundcomprises a trimer of dimercaptodioxaoctane.
 17. The coating compositionof claim 1, wherein the sulfur-containing compound comprises apolythioether.
 18. The coating of claim 1, wherein the sulfur-containingcompound comprises a polysulfide.
 19. The composition of claim 17,wherein the sulfur-containing compound comprises a prepolymer.
 20. Thecoating of claim 1, further comprising polyurethane and/orpoly(thio)urethane.
 21. The coating of claim 3, wherein the reactionbetween the isocyanate and the thiol is catalyzed by the amine in thesecond component.
 22. A method for coating a substrate comprising:applying to at least a portion of the substrate the coating compositionof claim
 1. 23. A method for coating a substrate comprising: applying toat least a portion of the substrate the coating composition of claim 20.24. A substrate coated at least in part with the coating of claim
 1. 25.A substrate coated at least in part with the coating of claim
 20. 26.The substrate of claim 24, wherein the substrate comprises at least aportion of a vehicle.
 27. The substrate of claim 25, wherein thesubstrate comprises at least a portion of a vehicle.
 28. The substrateof claim 26, wherein the substrate comprises a truck bed.
 29. Thesubstrate of claim 27, wherein the substrate comprises a truck bed. 30.The substrate of claim 24, wherein the substrate comprises at least aportion of a building structure.
 31. The substrate of claim 25, whereinthe substrate comprises at least a portion of a building structure. 32.The method of claim 22, wherein the first and/or second components ofthe coating composition are heated prior to application to thesubstrate.